Floor It!

Unless you are from the town of Bedrock, you probably want your rod to be fully equipped; running engine, working brakes, and floor pans. Every car must have these things; all of the other stuff is optional. A solid floor is not only attractive in a project, but also required for safety. Falling through the floor at 60 MPH would not be pretty. While Fred and his crew can stop a car with their feet, the rest of us mere mortals need steel separating the pavement from our little piggys.

Replacing floor pans is not for the squeamish. Seeing your project stretched out on the shop floor with no floors can be a little unsettling, especially for the uninitiated. In reality, it is not that difficult as long as you take your time, pay attention to the details, and have a good welder. A good gas-shielded wire feed is perfect for this task.

There are three ways to go about this task. You can use pre-fabricated patch panels, find a good donor car, or make your own. The easiest solution is aftermarket pre-fab patch panels. Most of the panels available in the aftermarket are good quality formed steel panels that come in small sections and as large as an entire floor. Most of the time you will only need to replace a specific section of a floor pan, and these products fill that need and are inexpensive. They don’t always fit very well if you need the whole section though, so you will likely have to make some adjustments along the way. Cutting the floor out of a donor car can be a double-edged sword, the cost can be very high for a donor car and you might have to make compromises on where to cut the donor floor in order to have enough material to weld it to the other car. Making your own patch will work, when you can’t find another panel, but the floor won’t have the original contours (if you need them) and can be a difficult task for a beginner.

When we came across this 1962 Mercury Comet wagon, we knew we had to have it. The body was in great shape; except for the total lack of useable floors. Unfortunately, we were looking at the car for a buddy, and he bought it. About 3 weeks later, he decided it was going to be too much work since it had no floor from the firewall to the rear seat. Opportunity knocked and we brought the car home. A quick call to Dearborn Classics and the new replacement floor pans were on the way.

Since this is a subframe car, the floor (along with the rocker panels) holds the car together. This makes the process more important because if the floors are not installed properly, the results would be disastrous. For an expert job, we took the car to Ramsey and Son Automotive in Stillwater, OK. Toby Ramsey and Jordan Lewis put the welder to work on the Comet and let us watch. Toby told us the key to a good install is the tools. A gas-shielded wire feed MIG welder is necessary. Along with that, you should have a sheet metal hole punch, spot weld cutters, an air hammer (with a body ripper and a spot weld breaker), die grinder with grinding pads, cut-off wheel, and your basic hand tools. A plasma cutter is a real time saver if you have access to one. The original floors are spot welded about every 2-3 inches along the rocker panels and the support braces. These are identified by the small dimple in the pan. If you can’t see them (often the rust is too severe) you can always cut around the braces and use an air hammer and a spot weld breaker to remove the rest.

If the rocker panels are shot, you must support the body between the doors before removing anything. A spreadable clamp is great, but a piece of square tubing cut to fit and tack welded in place works too. The body of the Comet was in great shape, other than the floors, so we didn’t need this step. Since the floors were in such bad shape, we had to use the entire sections in the Comet. Luckily, the pans from Dearborn Classics were a perfect fit, we only had to trim a couple of small sections.

The floor pans were installed in about two and a half days, including the hand formed sections we needed for under the rear seat (not available aftermarket). Once installed, Jordan Lewis coated all of the edges with seam sealer and sprayed the entire floor with Al’s Liner, a new product similar to truck bed liner. This stuff goes on nice and thick, ensuring the rust will never return. With the job done, the Comet has a whole new life, ready for a fire-breathing 347 stroker motor and some retro interior. No more Flintstone action here.

1. The original floor had rusted away to nothing. Even where the floor is there it is paper thin. The entire floor, from the toeboards to under the rear seat has to be replaced. Thankfully, the trans tunnel is good, at least most of it.

2. The new pans from Dearborn Classics fit great, but they only cover from the rear seat forward. We will have to build our own pan for the area under the seat. Toby Ramsey test fits the pan and marks it with a sharpie.

With the pan removed, he then measured down about two inches, leaving plenty of room for an overlap joint and marked it with a straight edge.

4. Then the plasma cutter was used to trim away the offending metal. If you do not have a plasma cutter, you can easily use a cut-off wheel or a body ripper and an air hammer.

5. The rest of the floor was cut out with the plasma torch, being careful to cut around the subframe support.

6. Once the bulk of the floor was gone, Ramsey used the air hammer, with a spot weld cutter attachment, to trim away the sections that were welded to the subframe and rocker panels. Another method, which takes longer, is to use a spot weld cutter such as a rotabroach or spot weld drill bit. The air hammer is really fast and does not damage the underlying metal.

7. The old floor was set off to the side. We will need the seat belt support discs and the seat support later.

8. Ramsey uses a punch\flange tool to punch holes in the new floor pan for new spot welds.

9. In order to set the spot welds in the right place, the distance from the rocker panel to the subframe rails was measured and notated.

10. These measurements were translated to the new pans and then holes were drilled for spot welds every few inches. A 3\8” bit was used to ensure adequate spot welds.

11. The subframe, rocker panels, and torque box sections were treated to a wire wheel cleaning in preparation for welding.

12. Then each section of metal, that was to be welded on, was sprayed with a weld-thru coating. This high-zinc coating protects the new metal and fresh weld from rusting in the future, particularly where it can’t be painted afterwards, such as inside the subframe. Rust is very hard to get rid of, and even though we wire brushed it, some rust still remains in the pitted areas. The remaining sheet metal in the car was sprayed with Al’s Liner Formula 62, a new rust killer to protect the metal from future rust.

13. The new floors were tacked in place, holding the pan in position while the rest of the pan is adjusted.

14. The subframe spot welds can be tricky, so Ramsey uses a spotlight to make sure the metal is lying flat. If it is not, a little tap with a hammer corrects that.

15. The tranny tunnels side of the pan were a hair long in the car, so the body ripper was used to trim it up in the car. You would not want to use a plasma torch here.

16. The rear pans started out as flat sheet metal, which Ramsey sprayed with weld-thru coating and a little undercoating.

17. With the flat metal in position, Ramsey used a hammer to break the edge over (yes, claw hammers are acceptable body hammers). A true body man, Ramsey makes this look easy.

18. The pan was then stitch welded in place. Stitch welding is done by placing a series of tack welds every few inches until the entire perimeter is welded. This reduces warping.

19. The sheet metal was measured and drilled for spot welds to the torque boxes like the front pans.

20. We also made up a tunnel patch panel. We left the tunnel in place until the rest of the floors were done so that nothing would sag or otherwise shift.

21. The floors are basically done at this point. The welds still need to be dressed with a grinder.

22. With everything cleaned up and wiped down with thinner, to get any residual grease or oil off the pans, Jordan Lewis treated the seams with seam sealer. This stuff protects the new welds, keeps moisture from getting to the edges of the metal, and fills any pinholes or gaps in the joint.

23. Once the seam sealer had dried (about an hour) Lewis mixed up some Al’s Liner and sprayed the entire floor from the tailgate to the firewall. This stuff is great, and it covers so well you can barely tell any work was done.

A life-long gearhead, Street Tech Magazine founder and editor Jefferson Bryant spends more time in the shop than anywhere else. His career began in the car audio industry as a shop manager, eventually working his way into a position at Rockford Fosgate as a product designer. In 2003, he began writing tech articles for magazines, and has been working as an automotive journalist ever since. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin’, Mopar Muscle, and many more. Jefferson has also written 5 books and produced countless videos. Jefferson operates Red Dirt Rodz, his personal garage studio, where all of his magazine articles and tech videos are produced. You can follow Jefferson on Facebook (Jefferson Bryant), Twitter (71Buickfreak), and YouTube (RedDirtRodz).